Apparatus for forming inner bevels in expansible tubes



May 4, 1954 R. E. scHoRNsTHElMER 2,677,424

APPARATUS FOR FORMING INNER BEVELS IN EXPANSIBLE TUBES Filed Feb. 28, 1950 Patented May 4, 1954 UNITED STATES ATENT OFFICE APPARATUS FOR FORMING INNER BEVELS IN EXPANSIBLE TUBES Application February 28, 1950, Serial No. 146,805

2 Claims.

This invention relates to forming an inner bevel or taper at the end of a piece of expansible tubing.

It is an object of this invention to provide a method and apparatus for forming such an internal bevel at the mouth of a piece of expansible tubing.

It is a further object to provide bevel cutting apparatus of simple construction which can be easily operated.

It is also an object to provide such an apparatus which makes it possible to cut the desired taper accurately and consistently.

Other objects will be apparent from the description and drawing which follow.

As an example of the invention a specic embodiment will be described, but it will be understood that this is intended solely as an illustration and not as a limitation upon the scope of the invention.

In the drawing, Fig. 1 is a side elevation, partially `broken away and in section, of one embodiment of the invention;

Fig. 2 is a view in elevation partly cut away in section of the expansible tubing before treatment;

Fig. 3 is a similar view of the tubing after the bevel has been formed; and

Fig. 4 is a cross-section on line d-t of Fig. 1.

In Fig. 1 an assembly including a bed plate II and upright members l2, I2 is shown. The upright members l2, t2 contain housings for rotatable shaft i3 which is driven by a drive belt it passing around pulley Il! which is secured to the shaft. the cylindrical die member I5 which has a tapered cutting edge l5.

The hinged clamp l l, shown in section, is slidably mounted in the ways i8 of bed plate II and serves to hold the expansible, elastic tube I9 in position for the bevel cutting operation as well as to hold mandrel 2l in position within the open end of the tube i9. The mandrel 2i has a tapered portion 22 at that end of the mandrel which is inserted in the elastic tube, the smallest diameter of the tapered portion 22 being less than the inside diameter of the elastic tube le in order to facilitate entry into the tube. The opposite end or die and of the mandrel 2E has a guide section 2l having a diameter slightly less than the inside diameter of the die l5; thus, a sliding t is obtained between the parts when the guide section is inserted in the die. The end of the guide section 27 has a tapered portion 23 which facilitates entry of the guide sec Secured to the shaft I3 is tion 2l in the die I5. The diameter oi the body of the mandrel 2l, i. e., that part shown within the clamp in Fig. 1, is substantially greater than the normal diameter of the tube I9 and slightly greater than the diameter of the guide section 21.

Between the body of mandrel 2i and guide section 21 lies a circumferential groove 2d which is tapered to a diameter about equal that of the inside diameter of elastic tube I9. The taper of the circrunferential groove 24 is such that the smallest diameter is at that end of the mandrel adapted to be inserted into cylindrical die I 5.

The mandrel 2l, that portion of the elastic tube i9 in the clamp I1, the cylindrical die I5 and the shaft It are all arranged on a common longitudinal axis as shown.

In carrying out the bevelling process tube I9 is distorted by inserting mandrel 2I therein as shown in Fig. 1 so that the mouth of the tube contracts into 'and seats in the circumferential groove 24, the portion of the tube adjacent the mouth having a generally conical conguration. After the mandrel 2| is placed in the tube I9, the expanded portion of the tube along with the mandrel is secured in the clamp Il.

As the cylindrical die I5 is rotated, the clamp including the tube and mandrel is moved toward the die, guide section 2l passing into the interior of die I5. Asl the rotating cutting edge I6 of the die l5 engages the flexible tube It, a clean cut is made, resulting in severance of that portion of the tube which extends into the circumferential groove 24. After completion or the cutn ting operation, the clamp assembly is moved away from die I5 and the clamp opened. Mandrel 2| is then removed, allowing the tube to return to its original diameter, the nished tube 25 then having a generally conical inner bevel 25 at its mouth as shown in Fig. 3.

The method and apparatus of this invention may be used with any tube or hose which can be expanded beyond its normal diameter and which possesses sulcient elasticity so that it readily returns approximately to its original dimensions when the expanding force is removed. For example, the present invention is useful for bevelling elastic tubes or hose made of natural or synthetic rubber or rubber-like materials. It may be advantageous to use water or other suitable lubricating medium on the exible tube at the point to becut or on the cutting edge It of the die I5.

By suitable selection of the diameter of die iii and mandrel 2|, elastic tubing of any diameter `and any Wall thickness may be bevelled to any extent desired.

Obviously, tubes having no flange at the end could be treated in the same manner as is the flanged tube shown in the drawing.

Although I have disclosed specic embodiments of my invention, I do not intend to limit myself solely thereto, but to include all the obvious modifications and variations falling Within the spirit and scope of the appended claims.

I claim:

1. Apparatus for cutting an inner bevel at the mouth of an elastic tube comprising a rotatable open-ended thin-walled cylindrical die having a cutting edge at its open end, a mandrel arranged on a common longitudinal axis with said die, said mandrel having a tapered portion at each end thereof to facilitate insertion of one end of said mandrel in said die and the opposite end in a tube to be cut and having a body member and aY guide member with a circumferential groove disposed therebetween, the diameter of said body member being substantially greater than the inner diameter of said guide member, said cutting edge of said die having a diameter less than that of said body member and greater than that of saidguide member, meansv for clamping said tube about said mandrel with an end of said tube seated in said circumferential groove, means for rotating said die on a longitudinal axis, and means for inserting the end of said mandrel comprising said guide member into said rotating die;

2. Apparatus for cutting an inner bevel at an end of an elastic tube comprising a cylindrical die having an open end provided with a cutting edge mounted for axial rotation, a mandrel comprising a generally cylindrical body member and a generally cylindrical guide member secured together on a common axis and spaced apart by a conical zone tapering from the diameter of said body member to a diameter substantially less than that of said guide member, the diameter of said guide member being slightly less than the inside diameter of saiddie and the diameter of said body member being substantially greater than the diameter of said guide member and greater than the inside diameter of said die, means for clamping said tube about said body member of said mandrel with an end of said tube constricted about said conical zone positioned between said body member and said guide member of said mandrel, said clamped assembly and said die being mounted for movement toward and from each other along a common axis to insert said guide member into said die, and means for rotating said die.

References Cited in the iile of this patent UNITED STATES PATENTS Number Name Date 918,360 Olier Apr. 13, 1909 1,131,589 Allen Mar. 9, 1915 1,604,526 McCandless Oct. 26, 1926 1,635,710 Falor July 12, 1927 1,771,471 Waner et al July 29, 1930 1,876,775 Smith Sept. 13, 1932 1,984,730 Darling Dec. 18, 1934 2,023,576 Connelly Dec. 10,. 1935 2,041,818 Connelly May 26, 1936 2,280,883 Beach Apr. 28, 1942 2,293,178 Stocker Aug. 18, 1942 2,327,028 Dohrenwend Aug. 17, 1943 2,365,902 Powers Dec. 26, 1944 

